Although not every scientist agrees, emissions of
carbon dioxide from the combustion of fossil fuels, mostly petroleum,
natural gas and coal are considered to be a major factor in causing the
onset of global warming. Unacceptable rises in temperature are leading
to rising sea levels from the melting of polar ice and corresponding
climate changes may effect plant and animal life in otherwise temperate
zones.

Technological advances reduce the growth in energy
demand to around 1% below the rate of economic growth, but the world’s
demand for energy is expected to continue to rise exponentially,
particularly in respect to emerging economies such as China and India.
What is desired is a number of renewable sources of energy, not limited
by resource depletion (as is the case with fossil fuels) and that are
“clean” in that they emit little or no so-called “greenhouse gases”.
Renewable sources include wind and sea current power, but there is a
so-called “renaissance” in nuclear power, which is purported to meet
both criteria.

A rising awareness of the imminence of a peak in
crude oil production together with the increasing demands for energy of
the developing economies, together with concern over climate change has
stimulated interest in the replacement of stations due for closure,
extension of the operational life of some and the building of new
stations.

A nuclear power station of 1000 megawatt
electrical generation capacity (1000 MWe or 1 gigawatt electrical =
1GWe) requires around 200 tonnes (metric tons) of uranium per annum.
For example, the United States has 103 operating reactors with an
average generation capacity of 950 MWe expected to consume over 22,000
tonnes of uranium in 2005.

Uranium production is subject to the same
“Hubbert” cycle which characterised US oil production, which peaked in
1970. In spite of improved extraction technology it has declined since
then, so in that in 2005 around 65% of US oil demand will be imported.
An individual uranium mine provides a rapid build-up followed by
uniform production over 5 –10 years after which it declines and is
closed. To maintain supply a series of mines have to be opened in
succession. The aggregate of the individual mine supply curves produces
a world “Hubbert” peak in uranium production which will eventually
limit the level of “once-through” nuclear power generation, whereby
spent fuel is not re-cycled.

This limit was recognised from the inception of
nuclear power resulting in several abortive attempts to develop fast
breeder reactors and waste recycling processes. In December 2002 ten
nations produced “A Technology Roadmap for Generation IV Nuclear Energy
Systems” which concluded that to extend the nuclear fuel supply into
future centuries it will be necessary to recycle used fuel and convert
depleted uranium rejected from the enrichment process to new fuel. Six
types of fast reactor were considered, each requiring US$ 1 billion to
take to a demonstration phase in 2025. The authors found it impossible
to choose between the six options and recommended “crosscutting
R&D”between rival participants.
(1)

MIT’s study “The future of nuclear power” opted for the “once-through”
mode in which discharged spent fuel is sent directly to disposal.The team believe that “the
world-wide supply of uranium ore is sufficient to fuel the deployment of
1000 reactors over the next half-century”.In
an appendix (5.E) they argue that the extraction of low concentrations
of uranium in phosphate deposits will suffice for a programme ending
with a “1500 GWe scenario”by
mid-century. (2)

The World Nuclear Association (WNA) also
recognises that regular mined supplies of uranium are limited and sees
the survival of its industry in the universal occurrences of uranium in
the earth’s crust and in seawater.

In judging the sustainability of nuclear power the
continuing availability of its uranium-based fuel is the main
consideration. As will also be shown, the carbon emissions from the
overall nuclear fuel cycle are inversely-proportional to the
grade of ore from which its uranium source is extracted, the lower the
grade, the more carbon dioxide is emitted.

2. Could all our energy be supplied by
nuclear power?

Before considering alternative sources, it is
necessary to understand the size of the problem by examining current
global energy consumption. Energy units exhibit little uniformity, but
the joule can be used as a universally acceptable basis for analysis.
Big numbers have to be employed to express global energy parameters,
i.e., the exajoule (joule x 1018) and the petajoule (joule x
1015), abbreviated as EJ and PJ respectively. The world’s
energy consumption in 2004 was 430 EJ, of which fossil fuels provided
90% as primary energy.Of this 63 EJ was
in the form of electrical energy, with only 10 EJ of it provided by
nuclear generation.

If not restrained by uranium supply problems,
nuclear power could in theory substitute for gas and coal for all the
world’s electricity generation, but electricity is not readily
adaptable for mobile transport.

Transport constrained to fixed guide systems, such
as rail and tramways can use electrical energy directly from current
collectors, but mobile transport able to move on roads or rough terrain
uses mostly liquid fuels derived from oil. As oil reserves deplete,
liquid fuels will be synthesised increasingly from natural gas and then
coal, until all fossil fuels able to be economically extracted are
exhausted.

To use electrical energy as an alternative to
conventional liquid fuels for mobile transport requires the production
of hydrogen from electrolysis and its subsequent cryogenic liquefaction
for on-vehicle storage. This has an inherent energy penalty over the
derivatives of primary fuels and of course, unless the electricity used
to produce the hydrogen fuel is from a renewable and “clean” source,
offers no panacea to global warming. Assuming mobile transport requires
40% of global energy and taking into account the energy loss in
conversion, the requirement for global electrical generation rises from
430 EJ to 700 EJ. The problem is that electrical energy of whatever
means of generation is a poor substitute for the adaptable primary
energy obtained from fossil fuels.

Assuming world economic growth of 3%/annum, with
growth in energy requirements 1% less, extrapolating from 2005 to 2020,
increases the energy requirement to 980 EJ.

A typical 1200 MW nuclear power plant produces 32
PJ per annum, so to provide for 700 EJ around 22,000 nuclear power
stations would have to be built. To provide for 980 EJ would require
30,000 stations, each requiring 200 tonnes/annum of uranium fuel. To
fuel this number of stations, around 6 million tonnes/annum of uranium
production would be required.

In 2004 world annual mine production totalled only
39,000 tonnes/annum of uranium, of which Canada produced 12,000 tonnes
and Australia 9,000 tonnes resp. Only Canada has reserves of high grade
ore, while the grade of the ores remaining in Australia progressively
lowers. The balance of 29,000 tonnes required to meet the 2004 nuclear
generators’ demand for 68,000 tonnes/annum came from inventories,
ex-weapons material, MOX and re-worked mine tailings. This secondary
uranium supply is due to run out within a decade, so primary production
would have to be increased 150-fold to match the anticipated global
energy needs exclusively from nuclear power in 2020. (3)

From the above projections it is clear that
nuclear power has no chance of matching the coming energy deficit by
supplying the needs of an equivalent hydrogen economy to that currently
sustained by fossil fuels. Even if there was sufficient uranium to fuel
it, the building of a parcof
30,000 nuclear power stations would be an impossible prospect. The
processing and sequestering of the consequential enormous volume of
radioactive waste would be also be an impossible task.

3. Can the world’s electrical energy
be supplied by nuclear power?

The MIT team have produced a more modest plan for
the building of power stations to provide 1,500 GWe of nuclear
generation capacity by 2050, which would provide 13,140 terawatthours
per annum (TWh), about a third of the anticipated global total
electricity consumption of 39,000 TWh in 2050. The uranium requirement
for their programme over the 45 years from now to then amounts to 9.5
million tonnes. In 2050, the uranium demand would be 306,000
tonnes/annum, which would require an 8-fold increase in current mining
production rates. But they assume a total uranium consumption for their
scenario of 17 million tonnes, because the average remaining life of
the parcafter 2050 would
require a further 7.5 million tonnes.

Uranium reserves of ore of a sufficiently high
grade (see 5 below for a definition of this) are
estimated at only 3,500,000 tonnes. So to get round this difficulty,
MIT compute that the reserves can be expanded to suit the requirement
by progressive increases in the uranium price. They consider that ore
deposits of grades between 0.001% and 0.03% would hold 22 million
tonnes of uranium and would be viable at increased uranium prices
without unacceptable consequent rises in the electricity price.
However, with the processing of these low ore grades there is a yield
loss and larger energy inputs, leading to a negative energy gain in the
overall nuclear fuel cycle.

In 2050 when reactors of 1500 GWe generation are
in service, if the required 306,000 tonnes/annum of uranium were to be
extracted from the best of the low grade ores, i.e., 0.03%, with an
optimistic yield of 50%, the mining of 2 billion tonnes of rock, plus
the removal of the over-burden, would be needed every year. Assuming
that by 2050 the best of the ores has been taken, to extract the same
from the lowest remaining, i.e. 0.001%, the yield would be even lower
at say 10% and the production of 306,000 tonnes of uranium would
require the mining of 300 billion tonnes of ore, plus the overburden.
(4)

World phosphate mining results in 150
million tonnes of phosphogypsum accumulating every year in diverse
locations as a waste product containing 10-20 ppm of uranium. If the
uranium was extracted it would only produce 1,500 to 3,000 tonnes of
uranium, so its production as a co-product does not seem a viable
possibility.

The scale of such inconceivable operations and the
commensurate input energy provided largely by fossil fuels is totally
non-viable. MIT has failed to give the location of the low grade
deposits of uranium ore on which their programme depends or to examine
the methods of extraction and the energy consumption related to the ore
grades assumed.

There is no chance that a parcof 1500 GWe of nuclear power plants,
providing only one third of the projected electrical energy consumption
in 2050, can be fuelled.

4. Is there enough uranium to supply
the currently operating nuclear stations for their remaining years of
operation?

There is a current world building programme of
around 23 new stations, with some 39 further stations on order or
planned. Some existing stations are having their operational life
extended and some are now being de-commissioned. The current uranium
fuel consumption of 68,000 tonnes/annum supports 441 operating stations
averaging 834 MWe capacity.

As the secondary sources of uranium, which
currently provide 40% of the fuel demand are expected to be exhausted
by 2012, many of the operating stations will close within a decade for
lack of fuel, depending on how many have become obsolete and closed,
how many have their operation lives extended and how many are built and
commissioned in the intervening period.

The end of the price competition from secondary
sources might intensify mining activity and lead to a resurgence in
production, but to open new mines, always assuming that suitable
opportunities emerge to locate them, will take more than the
intervening years.

The current demand/supply situation is best
illustrated by Table 1.

Table 1 Uranium demand, mining production and
deficit in tonnes

Country

Uranium required 2005

(WNA)(5)

% of world demand

Indigenous mining production 2004 (UxC)(6)

Deficit

USA

22,397

33

835

21,562

France

10,431

15

0

10,431

Japan

8,184

12

0

8,184

Germany

3,708

5

77

3,631

Russia

3,409

5

2890

519

South Korea

3,011

4

0

3,011

UK

2,409

3

0

2,409

Rest of world

14,808

22

35,498

-20,690

Total

68,357

100

39,300

29,057

Unsurprisingly the USA, the world’s largest
consumer of oil and gas, turns out to be the biggest consumer of
uranium. The USA consumes 25% of the world’s oil production, 25% of its
gas and takes 33% of the world’s available uranium, while producing
only 4% of its requirements from its own mines.

France ranks second and relies on
nuclear power for 80% of its electricity. But since its own mines are
now worked out, it is the most insecure. Japan ranks next followed
by Germany, Russia, South Korea and the UK. The combined uranium
consumption of the principle seven nations with nuclear power totals
53,500 tonnes (78% of the supply), compared with their own primary
mining production in 2005 of only 3,802 tonnes (6% of the supply).

A parcof
around 450 nuclear power stations, maintained by the replacement of
ageing reactors and the building of yet more, would require a supply of
90,000 tonnes/annum, so that mining production will have to increase 2½
times in the next 7 years – an unlikely prospect.

In Canada, the leading supplier of uranium, two
mines have closed and two of the four operating uranium mines have
passed their “Hubbert” peaks as is shown in the plot below.(7)For
production to remain at its current a series of new mines will need to
be opened.

A shortfall in fuel supply seems inevitable and
the nuclear contribution of electricity generation will progressively
decline.

5. Is nuclear power “clean”?

Then the claim for the carbon-free status of
nuclear power proves to be false. Carbon dioxide is released in every
component of the nuclear fuel cycle except the actual fission in the
reactor. Fossil fuels are involved in the mining, milling, conversion
and enrichment of the ore, in the handling of the mill tailings, in the
fuel can preparation, in the construction of the station and in its
de-commissioning and demolition, in the handling of the spent waste, in
its processing and vitrification and in digging the hole in rock for
its deposition.

The lower the ore grade, the more energy is
consumed in the fuel processing, so that the amount of the carbon
dioxide released in the overall fuel cycle depends on the ore grade.
Only Canada and Australia have ores of a sufficiently high grade to
avoid excessive carbon releases and to provide an adequate energy gain.
At ore grades below 0.01% for ‘soft’ ores and 0.02% for ‘hard’ ores
more CO2 than an equivalent gas-fired station is released and
more energy is absorbed in the cycle that is gained in it. Ores of a
grade approaching the “crossover” point such as those in India of
0.03%, if used, risk going into negative energy gain if there are a few
“hiccups” in the cycle.

The Olympic Dam mine in Australia, described as
potentially the world’s largest uranium producer, survives as a
co-producer of copper, silver and gold, but even so the uranium ore
grade averaging 0.04% is close to the “crossover” point of energy
viability. The future of the mine is the subject of a feasibility study
into its conversion from an underground to an open pit 3km x 3km x 1km
deep, with large potential for emissions of carbon dioxide. As the
price of diesel rises, the incentive for Australians to import
expensive oil to provide others with nuclear energy reduces.

The industry points to the presence of uranium in
phosphates and seawater, but the concentrations are so low that the
energy required to extract it would exceed many times the energy
obtained from any nuclear power resulting and the resulting carbon
emissions would be massive.

When the energy inputs, past, present and future
are totalled up and set against the actual energy derived from the
entire nuclear power programme and its waste handling, it may well be
that the overall energy gain has been negative. This has been masked by
the availability of cheap fossil fuels, but as that era passes it
behoves energy professionals to make an honest assessment of the energy
and monetary economics of proceeding further with a failed technology.

6. Global warming

Maybe the world does not need to stop all
carbon dioxide emissions, but even if a doubling of nuclear generation
capacity were possible it would only provide 20 EJ, i.e., 5% of world
energy consumption as electricity. There is no possibility of an
extension of nuclear capacity solving to any significant degree the
problem of global warming.

It is claimed that nuclear power meets the two
characteristics of sustainability and zero or low carbon dioxide
emissions and so might be able to substitute for fossil fuels once they
are exhausted and in the meantime to avoid release of some greenhouse
gases. The claims are baseless.

In conclusion, perhaps the scale of global warming
has been overstated by omitting to take into account fossil fuel
depletion. A guide to the maximum amount of carbon dioxide released
from the combustion of fossil fuels can be calculated, given that they
are limited. The graph below shows that if economic growth continues as
currently, the reserves of oil, gas and then most of the coal will have
emptied by the end of the century. From a knowledge of the carbon
content of the three fuels, it is then possible to work out the total
amount of carbon dioxide likely to be released.

This comes out as 5 exagrams or 5,000 billion
tonnes.

An earth scientist should be able to work out the
temperature rise that the release of this limited amount, mostly over
the next 50 years, is likely to produce. Before hampering the world
with useless measures unable to reduce the eventual amount of the
release of carbon dioxide, it would be more appropriate to estimate the
ultimate consequences of today’s immoderate exploitation and exhaustion
of fossil fuels.

The real problem the world faces is the depletion
of fossil fuel reserves – the very same depletion will ease the carbon
burden of the atmosphere by an inexorable emptying of its energy
resources by the world’s economies.